staging: ti-soc-thermal: return error in case power switch is not supported

Improve ti_bandgap_power by returning an error code in case
the device does not support controlling its power state.

Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed